DESCRIPTION (Adapted from the application) The goal of this In vivo Studies Core is to enhance research that elucidates roles of peptide hormones in the regulation of gastrointestinal functions by using animal models. The core is organized to bring together expertise and in vivo techniques for animal study. The core will provide the human resources, facilities, new technology and equipment necessary for in vivo experiments. The following major services will be provided to the center investigators: 1) To make available a various acute and chronic animal models; 2) To examine the physiological changes in mouse models following transgene expression or gene mutation; 3) To provide various in vivo techniques and tests for the investigation of physiology and pathophysiology of GI peptides in human being; 4) To facilitate innovative methodology and to develop new and sophisticated techniques for in vivo studies; and 5) To provide education and consultation on the application of in vivo techniques. Besides various services, special equipment, education, and consultation for animal studies, the core has been very active in developing new techniques for in vivo studies during the previous funding period. These new techniques include PET imaging system, evoked corticol and spinal potential studies, electrogastrography, and in vivo unit activity recording of neurons. These new technological developments significantly stimulate the in vivo studies in the center. In addition, a particularly useful function provided by this core is the coordination of human tissue collection for in vitro studies. This service greatly facilitates the availability of human GI tissue for cell and molecular biology studies.